Application of a proposed TLS model in a Lean Productive System


  • Rui Manuel Ferreira Dias Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa
  • Luis Diogo Silva UNIDEMI,FCT,UNL
  • Alexandra Tenera UNIDEMI,FCT,UNL



Continuous Improvement, TOC, Lean, Six-Sigma, TLS


The current market, becoming more rigid, forces companies to search continuously for innovation and improvement of their processes and products as a way to keep competitive and gain strategic advantages. Due to the global economic crisis, more and more companies try an approach through new management methodologies that allow better performances in terms of earning, profit and cost reduction. The present article proposes an integrated TOC (Theory of Constraints), Lean and Six-Sigma (TLS) model, with the objective of improving continuously a productive system, although it shows flexibility to be applied in other kinds of systems. The model synergistically integrate the best practices found in existing TOC, Lean and Six-Sigma models. The proposed model derivatives mainly from Eliyahu Goldratt’s TOC model of the “5 focus steps” and TLS model “Ultimate Improvement Cycle”, developed by Bob Sproull. The proposed TLS model was tested on an important Portuguese Manufacture. The implementation of a first continuous improvement cycle was completed and a second cycle began. The main results obtained by the implementation of the TLS model were extremely satisfactory.

Author Biographies

Rui Manuel Ferreira Dias, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa

Is a PhD student of Industrial Engineering at Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Portugal with a MBA in Management from FEUC in 2009 and a degree in Chemical Industry from FCTUC in 1987.

Quality, Enviromental and Food Safety Manager of Refrige – Coca-Cola Portugal; Industrial Manager in Equipar – Amorim Group; Operation Manager of A&I – Amorim Group since 2009.

Interest’s area is Quality Management, Operation Management, Food Safety, Lean, Six Sigma and Theory of Constraints.

Luis Diogo Silva, UNIDEMI,FCT,UNL

Holds a MSc degree in Engineering and industrial management

Alexandra Tenera, UNIDEMI,FCT,UNL

holds a MSc degree in Business Management Sciences (from ISCTE, Portugal) and a PhD degree in Industrial Engineering (from FCT/UNL, Portugal). She is an Assistant Professor of Industrial Engineering at Faculdade de Ciências e Tecnologia (FCT), Universidade Nova de Lisboa (UNL). Her scientific research has been on Production and Management Sciences focused in project and manufacturing management systems and practices improvement which has been published in international journals and conferences. She has been a researcher at FCT R&D Unit in Mechanical & Industrial.


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